Fresh water is no longer considered a ‘free’ resource of nature. It is common knowledge that much of the freshwater sources in the world today are polluted and not adequate for human consumption. A bottle of clean, purified water is currently sold at a higher price than that of oil. Polluted drinking water creates various forms of water related diseases, such as anemia, arsenicosis, cholera, malaria, and lead poisoning. Advanced countries and companies notice that this water shortage problem will become worse, and counteract by securing water-related technologies to monitor, clean, move, store, and dispose waters. The topics of particular and major technological and societal interest on the water-energy nexus are the development of:                (a) water desalination technology—more scalable (potable), inexpensive, and efficient devices to remove salts from brackish/seawater/produced water,        (b) water purification technology—more scalable (potable), inexpensive, and efficient devices to remove detrimental biological agents and other contaminants, including toxins, proteins, bacteria, cells and colloidal pollutant particles.        (c) water monitoring technology—more scalable (potable), inexpensive, and time-economical devices to preconcentrate/detect detrimental biological agents (especially for ultra-low concentration targets, e.g. Escherichia coli).        
Prior attempts to use ion concentration polarization to desalinate water had difficulties in that the electrodes were connected to the ICP zones with long microchannels creating unnecessary power consumption along the way. In addition, electrodes exposed directly to the desalting flow, and allow them to affect the systems performance and the quality of desalted water by Faradic/chemical reactions. For example, chlorine ions which are the most abundant ions in ground water, can be oxidized and disproportionated at anode, generating poisonous chlorine gas and hydrochloric acid (HCl)/hypochlorous acid (HOCl), respectively. With the problems on the water quality, the additional hydrogen ion (H+) production can worsen the energy consumption to reject those ions. The standard potential of the chlorine oxidation is only 1.39V, so corresponding pH change by its disproportionation in aqueous solutions was observed even in capacitive deionization (CDI) operated under 2 V. Improvements in such technologies are required.
Electrocoagulation (EC) is an electrochemical water treatment method, in which the metal ions released from the anode results in coagulation. The electrolysis of a sacrificial metal anode acts as a coagulant to destabilize colloidal particles that may be difficult to remove. Traditional EC is effective at removing suspended solids, organic hydrocarbons, and biological organisms, which are typically larger than salt ions. The resulting floc can be removed by physical separation methods, such as sedimentation or flotation. Typically, traditional EC removes small particles and little salt is removed during the process.